Along with rapid development of the Internet and popularization of large-screen multifunctional mobile phones, a great deal of mobile data multimedia services and various high-bandwidth multimedia services emerge, such as the mobile data multimedia services of video conferencing, television broadcasting, video on demand, advertising, online education, interactive games and the like. On one hand, increasing service requirements of mobile users are met. On the other hand, new service increasing points are also brought to mobile operators. These mobile data multimedia services require that the same data can be received by a plurality of users simultaneously, and have the characteristics of large data volume, long duration, sensitivity to time delay and the like compared with ordinary data services.
In order to effectively utilize mobile network resources, the 3rd Generation Partnership Project (3GPP) raises an MBMS, which is a technology through which data is transmitted from a data source to a plurality of targets, such that resources on the network (including a core network and an access network) are shared and a utilization rate of the network resources (particularly, air interface resources) is increased. The MBMS defined by the 3GPP can implement multicast and broadcast of pure-text and low-rate message and can also implement broadcast and multicast of high-speed multimedia service and provide various videos, audios and multimedia services, which undoubtedly complies with the tendency of development of mobile data in the future and provides a better service prospect for development of 3G.
In Long Term Evolution (LTE), an MBMS may be sent in a multicast mode, called a Multicast/Broadcast over Single Frequency Network (MBSFN) sending mode. The MBMS service sent in the multicast mode is also called an MBSFN service in which a plurality of cells may adopt the same modulation and coding scheme and send the same content by adopting the same physical resource.
Multi-cell transmission of the MBMS has the following characteristics:
1) the MBMS is synchronously transmitted in an MBSFN area;
2) multi-cell MBMS transmission combination is supported;
3) a Multicast Traffic Channel (MTCH) and a Multicast Control Channel (MCCH) are mapped to a Multicast Channel (MCH) in a Point-to-Multipoint (p-T-m) mode; and
4) an MBSFN synchronization area, the MBSFN area, MBSFN transmission, advertisement and a preservation cell are all semi-statically configured through operation and maintenance.
In such a manner, User Equipment (UE) of a plurality of cells may receive a plurality of pieces of MBMS data with the same contents and perform SFN combination, thereby increasing a gain of received signals. A plurality of cells which send the same MBMS by adopting the same physical resource in the MBSFN sending mode form an MBSFN area.
During practical LTE networking, a plurality of MBSFN services exist in an MBSFN area, and all of these MBSFN services belonging to the same MBSFN area form an MBSFN service group. That is, an MBSFN service group belongs to only one MBSFN area. An MBSFN area includes a plurality of cells, and identical MBSFN service groups are configured for the respective cells. Data channels MTCHs with a plurality of MBSFN services of the same MBSFN area and a control channel MCCH of the MBSFN services may be multiplexed onto an MCH. An MCCH and a plurality of MTCHs (i.e. a plurality of logical channels) of the same MBSFN area may be mapped to the same transmission channel MCH; and the MCH operates as a bearer through a Transport Block (TB) of an MBSFN subframe.
In an existing public technology, an MCH Subframe Allocation Pattern (MSAP) occasion is simultaneously introduced into the concept of MSAP, and it indicates all multicast resources contained in an MCH corresponding a certain MSAP within a time period of a dynamic scheduling period. In an MSAP occasion, a plurality of MTCHs and dynamic scheduling information may be sent, and an MCCH may also be used, in which the dynamic scheduling information is born in a Control Element (CE) of a Media Access Control (MAC) Protocol Data Unit (PDU), wherein a time length of the MSAP occasion may be 320 ms. The time length of an MSAP occasion is a scheduling period, and is also called a dynamic scheduling period. One or more MBSFN subframes of one or more MBSFN frames are allocated to an MCH allocates through an MSAP, in which a subframe sent in a multicast mode is called an MBSFN subframe, and a frame containing an MBSFN subframe is called an MBSFN frame.
On each MSAP occasion configured in an MCH, dynamic scheduling information is born, mapping information from MTCHs to auxiliary MSAP subframes is contained. The mapping information is determined by using the relationship between the No. and index of an MBSFN subframe in a scheduling period. UE may read the scheduling information to know allocation of each MTCH on the MBSFN subframes, and the UE can read MTCH of interest from the corresponding MBSFN subframe and neglect the MBSFN subframes not required to be read, so that the efficiency in which MBMS is received by the UE is improved, and power consumption of the UE is reduced. Herein, Nos. of MBSFN subframe are determined by sequentially arranging and numbering all MBSFN subframes allocated by an MCH within a scheduling period.
In an existing LTE technology, an MCH is multiplexed by a plurality of logical channels in a manner as follows: a subframe corresponds to a Transmission Time Interval (TTI), a TB may be sent in a TTI and each data TB corresponds to a MAC PDU. A MAC PDU may contain a plurality of MAC Service Data Units (SDUs) which may be from different logical channels including for example an MTCH, an MCCH and the like. Data from different logical channels is connected in series in the MAC PDUs and then sent together over a physical channel.
A clustering communication system is a dedicated wireless communication system developed to meet commanding and scheduling requirements of the users of the industry and oriented to a specific industrial application, in which there are numerous wireless users sharing a small number of wireless channels and which takes commanding and scheduling as main applications, and is a multipurpose and high-efficiency wireless communication system. A clustering communication system is widely applied to the fields of government departments, public safety, emergency communication, power, civil aviation, petrochemical engineering, military and the like. In 3GPP LTE, clustering communication is called Group Communication Service Enabling (GCSE). At present, a probability that clustering communication is implemented by adopting an MBMS technology is under discussion in the industry.
In a process of researching and practicing a conventional art, it is found that the conventional art has a problem as follows:
in case of a network error, how to timely send a clustering service born by an MBMS to UE to avoid a incapability of sending data or an significant delay occurring when the data is sent is a problem urgent to be solved by the conventional art.